bouyancy control tip

[Charlie99]

what on earth is this person talking about?

Your position relative to the "junk" in the water gives you direct, obvious, instantaneous feedback of relative motion.

The depth gauge/computer readout is typically updated only once per second and doesn't give a immediate indication of ascent/descent speed.

In practice, I use both. The computer gives me absolute depth numbers and isn't affected by upcurrents/downcurrents. The junk in the water give immediate feedback on small up/down movements.

Yes, I can fly-by-instruments by solely relying upon the depth gauge, but why work so hard when there's an easier way.

 

[Uncle Pug]

Besides that... the ctenophores and siphonophores are more fun to look at than a digital read out.

 

[IndigoBlue]

Besides that... the ctenophores and siphonophores are more fun to look at than a digital read out.

Guess I'm just a perfectionist then, when it comes to 30 ft per MINUTE. I can wait to enjoy the ctenophores and sipnophores until the safety stop(s).

[edited for typos]

 

[The Kraken]

Flying by the instruments has saved my butt many, many times. And old adage from an old pilot - "Trust your instruments!". An instrument may be in error or out of calibration but it does not panic nor is it subject to vertigo and spatial misorientation.
Today's computers update very quickly. I am not an expert on all of the dive computers by any stretch of the imagination, but the DataMax that I have updates very quickly. I doubt, seriously, that I can accelerate fast enough underwater to render the readings of my computer invalid.
I must agree, however, with Uncle Pug and Charlie99 that using a relatively fixed vertical reference is an excellent way to assess one's ascent. And, as Indigo Blue so succintly puts it, "Two of everything . . .".

 

[String]

Currents even small ones can make the tiny stuff in the water move up and down over shortish distances so its not a great indicator. Also if the water is absolutely thick with plankton or have horizontal currents its not great.

I use my computer for ascent rate with no visual references and before that (and when i forget it) just my watch and depth gauge. Works nicely.

 

[ArcticDiver]

.

 

[ArcticDiver]

There's nothing like a direct visual reference in the water. Keeping your eyes planted on a gauge that only tells you when you've moved an entire foot doesn't do a thing for you. It's hard to get that display to change once every two seconds (or once every 3 seconds, or once every 4 seconds) to properly time your ascent.

Flying by an instrument is crap.

Looks like you've never enjoyed the experience of ascending in a plankton bloom. If you had you'd realize that using either/both the computer or SPG readings are the absolutely best way to determine depth as a diver makes a controled ascent.

 

[Snowbear]

Besides that... the ctenophores and siphonophores are more fun to look at than a digital read out.

Yep! More accurate for maintaining position in the water (horizontal OR vertical) than a guage as well. I found that looking at their guts and cilia with the magnifyer gadget requires absolute buoyancy control to keep them in the field of vision.
IB's right about one thing, though - for determining actual depth, a guage is helpful.
AD - I'm not clear on how an SPG helps determine depth, though?

 

[Uncle Pug]

Guess I'm just a perfectionist then, when it comes to 30 ft per second. I can wait to enjoy the ctenophores and sipnophores until the safety stop(s).

But I think most folks would call 30 ft per second a ballistic ascent.

I prefer to keep my ascent at 30 ft per minute between stops and less than 5 ft per minute for the last 20 feet to the surface.

 

[IndigoBlue]

But I think most folks would call a 30 ft per second a ballistic ascent.

I prefer to keep my ascent at 30 ft per minute between stops and less than 5 ft per minute for the last 20 feet to the surface.

Sorry ... meant 30 ft per minute.